Method and apparatus for dispersing a solid material in a liquid

ABSTRACT

A method and apparatus for dispersing particles of solid material in a liquid in which the particulate solid material is placed in a reservoir of the liquid in a closed vessel having a bottom outlet provided with an internal vertical standpipe through which the contents of the vessel are withdrawn and wherein the liquid is introduced into the vessel at an angle normal to and adjacent the open terminus of the standpipe. The concentration of solid particles in the withdrawn liquid is controlled by adjusting the velocity of the liquid introduced into the vessel, an increase in inlet velocity causing a decrease in the particle concentration. Where the particles are buoyant, the standpipe extends to the top of the vessel and the liquid is introduced at that point. In the case of nonbuoyant particles, a short standpipe is employed that terminates near the bottom of the vessel and the liquid is introduced adjacent thereto.

I United States Patent [151 3,653,638

Show'alter [4 Apr. 4, 1972 [54] METHOD AND APPARATUS FOR DISPERSING A SOLID MATERIAL IN A Primary Examiner-M y LIQUID Assistant Examiner-Robert J. Miller Attorney-Milton W. Lee, Richard C. Hartman, Lannas S. [72] Inventor: William E. Showalter, Seal Beach, Calif. Henderson, Dean Sandford and Robert E. Strauss [73] Assignee: Union OilCompany of California, Los An- 57] ABSTRACT geles, Calif. A method and apparatus for dispersing particles of solid [22] Fned' June 1970 material in a liquid in which the particulate solid material is [21] Appl. No.: 47,361 placed in a reservoir of the liquid in a closed vessel having a bottom outlet provided with an internal vertical standpipe through which the contents of the vessel are withdrawn and wherein the liquid is introduced into the vessel at an angle non 5x 1 Field 6: Search ..137/3, 1, 268, 604; 210/169, ma] P P F P F' The 210/206 242 23/271 272 7 267- 259/4 concentration of solid particles in the withdrawn llquld 15 controlled by adjusting the velocity of the liquid introduced into I 56] Reterences Cited the vessel, an increase in inlet velocity causing a decrease in the particle concentration. Where the particles are buoyant, UNITED STATES PATENTS the standpipe extends to the top of the vessel and the liquid is introduced at that point. In the case of nonbuoyant particles, a 3,426,901 2/1969 Sherper ..210/169 Short standpipe is employed that terminates near the bottom 2,573,002 12/ 1951 Fryer 4 X of the vessel and the liquid is introduced adjacent thereto. 2,795,403 6/1957 Mead ..259/4 3,474,817 10/1969 Bates et a1. 137/268 19 Claims, 8 Drawing Figures PATENTEDAPR 4|972 3,653,638

SHEET 1 or 3 WAV AY/AV AV AV/(WAVAVAVAVAV/ INVENTOR.

14 44/444 i. Swan 4175? METHOD AND APPARATUS FOR DISPERSING A SOLID MATERIAL IN A LIQUID This invention relates to the dispersion of particulate solids in a liquid, and more particularly to methods and apparatus for dispersing a particulate solid material in a liquid flowing through a closed conduit. The method and apparatus of this invention is especially useful for dispersing particles of solid well treating agent in a liquid injected into a well penetrating a subterranean formation.

It is often necessary to disperse a particulate solid material in a liquid flowing through a closed conduit so as to obtain a relatively uniform dispersion of the solid particles in the liquid. However, problems are often encountered in that the wetted solid particles agglomerate to cause plugging of the dispensing or feeder apparatus, or to cause plugging of the conduit carrying the dispersion. Also, regulation of the concentration of solid particles in the liquid is difficult, particularly where it is desired to slowly add the particulate material to the flowing liquid, often requiring complex and elaborate equipment to control the rate of dispersion of the solid particles in the liquid.

These problems are encountered in dispersing particles of solid well treating materials, such as particulate plugging agents and the like, into fluids injected into a well penetrating a subterranean petroleum reservoir or other earth formation. H eretofore, difficulty has been experienced in dispersing these dry particulate solids in a liquid, such as flood water, and in controlling the rate of solids addition.

Thus, need exists for a simple, inexpensive device to disperse a particulate solid material in a liquid flowing through a conduit, and particularly for a device that is inexpensive, easily movable, and that does not require an external source of ower.

p Accordingly, a principal object of the present invention is to provide a method and apparatus for dispersing particles of solid material in a flowing liquid. Another object of the invention is to provide a relatively simple, inexpensive device for dispersing particles of solid material in a liquid flowing through a closed conduit which requires relatively little operating attention. Yet another object of the invention is to provide a method and apparatus for dispersing particles of solid material in a flowing liquid that does not require an external source of power. Still another object of the invention is to provide a method and apparatus for dispersing buoyant particles of solid material in a liquid flowing through a closed conduit. A further object of the invention is to provide a method and apparatus for dispersing nonbuoyant particles of solid material in a liquid flowing through a closed conduit. A still further object of the invention is to provide a method and apparatus for dispersing particles of a solid well treating agent in a liquid injected into a well penetrating a subterranean formation. Other objects and advantages of the invention will be apparent from the following description.

Briefly, the objects of the invention are realized by placing the particulate solid material in a reservoir of the liquid in a closed vessel having a bottom outlet provided with an internal vertical standpipe through which the contents of the vessel are withdrawn and introducing liquid into the vessel adjacent to the inlet terminus of the standpipe. In this manner, liquid entering the vessel passes across the open inlet end of the standpipe, thereby creating turbulence in the liquid containing the suspended solid particles, particularly in the vicinity of the inlet to the standpipe, which regulates the concentration of solid particles in the liquid withdrawn through the standpipe and prevents agglomeration of the solid particles and plugging of the standpipe inlet. The liquid entering the vessel displaces an equal volume of liquid containing suspended particles of solid material from the vessel through the outlet standpipe. The rate at which the liquid exits the vessel and rate of dispersion of solid particles are controlled by adjusting the volume of liquid introduced into the vessel.

The invention will be more readily understood by reference to the accompanying drawings, in which like parts are referred to by like numbers throughout, and wherein:

FIG. 1 is a top view of the apparatus of this invention;

FIG. 2 is a side elevation view of the apparatus;

FIG. 3 is a vertical sectional view taken along the line 3-3 of FIG. 1 showing an embodiment of the invention useful in dispersing buoyant particles of a solid material in a liquid;

FIG. 4 is a horizontal sectional view taken along the line 4- 4 of FIG. 2;

FIG. 5 schematically represents the relationship of inlet and exit conduits;

FIG. 6 is a' detail view showing the construction of the internal piping connections;

FIG. 7 is a vertical sectional view illustrating another em bodiment of the apparatus of the invention especially useful in dispersing nonbuoyant particles of solid material in a liquid; and

FIG. 8 schematically represents the apparatus of this invention employed todisperse particles of a solid well treating agent in a liquid injected into a well penetrating a subterranean formation.

Referring specifically to FIGS. 1, 2, 3 and 4 of the drawings, vessel 10 is a closed vessel comprised of a substantially cylindrical shell 12 having an integral top head I4 and an integral bottom head 16. Preferably, the length of the vessel is greater than its diameter, and more preferably the vessel has a length of about three to four times its diameter. The vessel can be conveniently fabricated from a short section of relatively large diameter pipe, and can be a pressure vessel of conventional design. 'Vessel 10 is supported in a substantially vertical position by a suitable supporting means such as the legs 22 which are equidistantly disposed about the vessel. Legs 22 are constructed of short sections of pipe and are provided with pads 24 for attachment to the vessel, and foot plates 26. Cross braces 28 attached to legs 22 and vessel 10 are provided to obtain additional rigidity. Other alternative means of supporting vessel 10. in a substantially vertical position can be employed.

Vessel I0 is provided with a top opening through which the particulate solid material is periodically introduced into the vessel, such as the threaded nozzle 30 fluid-tightly closed by valve 32 provided with funnel 36. Also, a pair of lifting eyes 34 are fixedly attached to the top head or elsewhere on the vessel to facilitate movement of the device between locations. Liquid is introduced into the vessel through conduit 40 and valve 42 connected to nozzle 44 in the side wall of the vessel. The vessel can also be provided with a pressure gauge 46 and pressure relief valve 48 to protect the vessel from excessive pressure. Vessel 10 is further provided with bottom nozzle 50 to which outlet conduit 52 containing valve 54 is connected, and a separate nozzle 56 to which conduit 58 containing valve 60 is connected to facilitate emptying the vessel of liquid. Valves 32, 54 and 60 are preferably gate or ball valves which provide a full diameter flow opening when the valve is in the open position. 7

As more particularly illustrated in FIGS. 3 and 4, bottom outlet nozzle 50 is fitted with standpipe 62 which projects upwardly into vessel 10 and terminates in an open end at a point about level with inlet nozzle 44 in a manner which will hereinafter be more fully described. Inlet nozzle 44 is provided with internal liquid inlet conduit 64 which conducts the incoming liquid from nozzle 44 to a point adjacent to the upper terminus of standpipe 62' at which point the liquid is discharged into vessel 10. Standpipe 62 and inlet conduit 64 can be provided with internal supports, not shown, if desired; however, such supports have generally not been found necessary.

Internal liquid inlet conduit is selected to have a crosssectional flow area of a size that provides an entrance velocity of the magnitude hereinafter described. The cross-sectional flow area of standpipe 62 is selected to provide a liquid velocity of a magnitude sufficient to overcome the buoyancy forces acting upon the particles, yet the standpipe must be of a sufficient size to avoid plugging.

The relationship of the upper terminus of standpipe 62 and internal liquid inlet conduit 64 is particularly illustrated in FIG. 5. Standpipe 62 is supported. in a substantially vertical position and internal inlet conduit 64 is supported in a substantially horizontal position so that an extension of their longitudinal axes intersect at a normal angle. The respective lengths of standpipe 62 and internal liquid inlet conduit 64 are selected so that the upper terminus of standpipe 62 is below the center line of conduit 64 a distance equivalent to about V2 to 2 times the diameter of conduit 64 and the distance between the end of conduit 64 and the center line of standpipe 62 is equivalent to about /2 to 2 times the diameter of the standpipe. The distance between the upper terminus of standpipe 62 and the center line of conduit 64 is illustrated in FIG. 5 by the dimension a and the distance between the end of conduit 64 and the center line of standpipe 62 is illustrated by dimension 12. Thus, with reference to FIG. 5, the respective lengths of standpipe 62 and conduit 64 are selected so that the dimension a is about /2 to 2 times the diameter of conduit 64 and the dimension [2 is about /2 to 2 times the diameter of standpipe 62. In one embodiment of the invention, conduit 64 is constructed of A-inch schedule 40 pipe having an outside diameter of 0.54 inch and standpipe 62 is constructed of inch schedule 40 pipe having an outside diameter of 0.675 inches, and the dimension a is from about 0.27 inches to 1.08 inches and the dimension b is from about 0.338 inches to 1.35 inches. In a preferred embodiment employing a 54-inch diameter internal conduit and a %-inch diameter standpipe the dimension a is about 0.50 inches and the dimension b is about 0.75 inches.

Both standpipe 62 and internal liquid inlet conduit 64 can be constructed of tubular material, such as small diameter steel pipe, or the like, and can be provided with an integral flanged or threaded means to mount the pipe in the respective nozzle of vessel 10. FIG. 6 illustrates one embodiment of standpipe 62 or conduit 64 adapted for use with an internally threaded nozzle. The illustrated embodiment includes a threaded member 70, such as a bushing or plug, drilled to accept the pipe 72. The pipe is secured to bushing 70 by weld 74, and is provided with threads 76 on the exterior end of vessel 10.

In the embodiment of the invention illustrated in FIGS. 2 and 3, the inlet terminus of standpipe 62 is located in the upper section of vessel 10 and discharge end of liquid inlet conduit 64 is maintained in proper relationship with the inlet of standpipe 62. In this embodiment, it is convenient to locate liquid inlet nozzle 44 in the upper section of the vessel, i.e., in the side wall of the vessel adjacent top head 14. This embodiment of the invention is particularly preferred where the particles of solid material are buoyant, i.e., where the particles float in the liquid. Where the particles are nonbuoyant, i.e., where they do not float in the liquid, it is preferred that the standpipe 62 be shortened so that the inlet terminus is located adjacent the bottom of vessel 10 as illustrated in FIG. 7. In this embodiment, liquid inlet nozzle 44 is located in the bottom section of the vessel so that the discharge end of conduit 64 is maintained in proper relationship with the inlet terminus of standpipe 62.

In operation, valves 42 and 54 are closed and a bulk quantity of the particulate solid material is placed in the vessel through nozzle 30. Valve 32 is closed to close the top opening and the valves 54 and 42 are opened to fill the vessel with liquid and to establish liquid flow through the vessel. The vessel is normally filled with liquid to at least the level of the top of the standpipe, and preferably is substantially completely filled with liquid. In the case where the particles are buoyant in the liquid, the particles float to the top of the vessel. The enterin g liquid passes across the upper terminus of the standpipe causing turbulence that maintains the standpipe inlet free of accumulated quantities of solid particles, maintains the level of the bulk of the buoyant particles depressed below the standpipe inlet, and regulates the discharge of solid particles from the vessel. The liquid entering the vessel through internal conduit 64 displaces an equal volume of liquid containing suspended particles of solid material from the vessel through outlet standpipe 62. At higher liquid inlet rates, not only is the volume of liquid withdrawn from the vessel through standpipe 62 increased, but the higher liquid inlet velocities create greater turbulence at the standpipe inlet, thereby decreasing the rate that particles are admitted to the standpipe. Thus, by proper regulation of the liquid inlet velocity, the concentration of solid particles in the withdrawn liquid can be controlled. As the dispersion operation progresses, buoyant particles continue to move upwardly in the vessel, being caught in the turbulent zone at the standpipe inlet, with some of these particles entering standpipe 62 and being discharged with the withdrawn liquid. This operation continues until essentially all of the particulate solid material is discharged from the vessel. Nonbuoyant solid particles are similarly discharged from a vessel of the type illustrated in FIG. 7.

It has been found that a solid particulate material can be satisfactorily dispersed in a liquid over a wide range of liquid inlet velocities, and while in the broad scope of the invention it is only necessary to introduce the liquid into the vessel at a velocity that provides sufficient turbulence to prevent agglomeration of the solid particles at the inlet to the standpipe or in the standpipe, it has been found that superior results are afforded and uniform dispersions produced at liquid entrance velocities between about 5 and 30 feet per second.

The method and apparatus of this invention can be utilized to disperse substantially any relatively finely divided solid materials in a liquid, and is particularly useful in dispersing particles of a solid material having mean diameters between about 0.1 micron and about /a inch. The method and appara tus is particularly useful in dispersing in a liquid relatively finely divided particles of solid well treating material and particularly the solid plugging particles, such as the solid oil-soluble, water-insoluble solid particles comprised of a homogeneous mixture of polymer, wax and resin components disclosed in U.S. Pat. No. 3,302,719; the solid particles comprised of a mixture of polymer and non-gaseous hydrocarbon disclosed in U.S. Pat. No. 3,316,965; the solid particles comprised of a homogeneous mixture of polymer and halogenated aromatic hydrocarbon disclosed in U.S. Pat. No. 3,342,263; the solid particles comprised of a homogeneous mixture of a polymer component and a solid alcohol disclosed in U.S. Pat. No. 3,363,690; and the solid particles comprised of petroleum wax or wax-polymer compositions having diameters within the range of about 1 to 50 microns disclosed in U.S. Pat. No. 3,455,390.

Various of the finely divided particulate solid well treating materials such as the aforementioned plugging agents are oleaginous, i.e., the surfaces of the solid particles are oil wettable. It has been found that where these materials are to be dispersed in an aqueous liquid, superior results are obtained by first preparing a slurry of the particles in the aqueous liquid. Such slurries can be conveniently prepared by employing a surface active agent that affects the water wettability of the particle surfaces. Thus, it is preferred to intimately admix the particulate solid material, an aqueous liquid and a surface active agent to form a slurry of the solid material in the liquid. This slurry is then placed in vessel 10 and the dispersion conducted in the above-described manner.

FIG. 8 illustrates the method and apparatus of this invention employed to disperse a particulate solid well treating material into a liquid injected into well penetrating subterranean earth formation 82. In this embodiment of the invention, a portion of the liquid passes through conduit 84 and into well 80 at a flow rate controlled by valve 86. Another portion of the liquid is withdrawn from conduit 84 upstream of valve 86 and passed through conduit 40 to vessel 10 at a rate controlled by valve 42. Vessel 10 is charged with a particulate solid well treating material as described above. A dispersion of particles of solid well treating material in the liquid is withdrawn from vessel 10 and returned through conduit 52 containing valve 54 to injection conduit 84 at point downstream from valve 86. The liquid containing the dispersed solid particles is injected into well 80 and passed downwardly through the well and into contact with the subterranean formation in conventional manner.

The dispersion method of this invention is further demonstrated by the following examples which are presented by way of illustration, and are not intended as limiting the spirit and scope of the invention as defined by the appended claims.

EXAMPLE 1 An aqueous dispersion of particulate solid well plugging agent is prepared and injected into a well penetrating a subterranean formation by the following technique. A slurry is prepared by intimately admixing 50 pounds of a particulate solid well treating agent comprised of particles of a homogeneous admixture of wax and polymer having diameters within the range of about 1 and 50 micron, 13 gallons of water and 40 cc. of a surface active fatty acid amide marketed by Onyx Chemical Company under the trademark Onyxol WW. This slurry is charged to a dispersion apparatus of the type specifically illustrated in FIGS. 2 and 3 of the drawings, and liquid flood water is introduced into the vessel through the internal inlet conduit at a velocity of about feet per second in the manner illustrated in FIG. 8. A relatively uniform dispersion of the particulate solid well treating agent in the liquid is withdrawn through the internal standpipe and admixed with an additional quantity of floodwater injected into a well penetrating an earth formation.

EXAMPLE 2 An aqueous dispersion of a particulate oleaginous solid material in an aqueous liquid is prepared by the following technique. A slurry is prepared by intimately admixing 50 pounds of a particulate solid wax-polymer composition having particle sizes within the range of about 8 to 100 mesh U.S. Standard Sieve, 13 gallons of water and cc. ofa surface active fatty acid amide marketed by Onyx Chemical Company under the trademark OWW. This slurry is charged to a dispersion apparatus of the type specifically illustrated in FIGS. 2 and 3 of the drawings, and water is introduced into the vessel through the internal inlet conduit at a velocity of about 5 feet per second. A relatively uniform dispersion of the particulate solid material in water is withdrawn through the internal stand pipe.

Next, the liquid inlet velocity is increased to about 15 feet per second. It is observed that the concentration of solid particles in the withdrawn dispersion is lower than obtained at an inlet velocity of 5 feet per second.

EXAMPLE 3 An aqueous dispersion of a water-insoluble particulate solid material having a density of about 1.2 is prepared by the following technique. A bulk quantity of the particulate material is placed in a dispersion apparatus of the type illustrated in FIG. 7 of the drawings. The vessel is filled with water and closed. Next, water is introduced into the vessel through the internal inlet conduit at a velocity of about 20 feet per second. A relatively uniform dispersion of the particulate solid material in water is withdrawn through the internal standpipe.

Various embodiments and modifications of this invention have been described in the foregoing specification, and further modifications will be apparent to those skilled in the art. Such modifications are included within the scope of this invention as defined by the following claims.

Having now described my invention, 1 claim:

1. Apparatus for dispersing particles of solid material in a liquid, which comprises:

a vessel adapted to contain a bulk quantity of the particulated solid material in a reservoir of the liquid;

an outlet connection in said vessel;

an internal standpipe communicating the interior of the vessel with said outlet connection, said standpipe having an open inlet terminus through which the contents of the vessel are withdrawn;

a liquid inlet connection in said vessel; and

an internal liquid inlet conduit on the interior of said vessel communicating said inlet connection with the interior of said vessel.

2. The apparatus defined in claim 1 wherein said internal liquid inlet conduit is adapted to discharge liquid into said vessel across the open inlet terminus of said standpipe in a direction normal to the longitudinal axis of said standpipe.

3. The apparatus defined in claim 1 wherein the inlet terminus of said standpipe is located in an upper section of said vessel, wherein said liquid inlet connection is located in the side wall of said vessel and wherein said internal liquid inlet conduit projects from said liquid inlet connection horizontally into said vessel so as to discharge liquid into said vessel across the inlet terminus of said standpipe.

4. The apparatus defined in claim 1 wherein the inlet terminus of said standpipe is located in a lower section of said vessel, wherein said liquid inlet connection is located in the side wall of said vessel, and wherein said internal liquid inlet conduit projects from said liquid inlet connection horizontally into said vessel so that the liquid discharged into said vessel passes across the open inlet terminus of said standpipe.

5. Apparatus for dispersing particles of solid material in a liquid, which comprises:

an elongated, closed vessel adapted to contain a bulk quantity of the particulated solid material in a reservoir of the liquid;

means to support said vessel in a substantially vertical position;

an outlet connection in the bottom of said vessel;

an internal standpipe vertically supported within said vessel to communicate the interior of the vessel with said outlet connection, said standpipe having an open inlet terminus through which the contents of the vessel are withdrawn;

a liquid inlet connection in said vessel; and

an internal liquid inlet conduit within said vessel to communicate said inlet connection with the interior of said vessel, said conduit being adapted to discharge said liquid into said vessel across the inlet terminus of said standpipe.

6. The apparatus defined in claim 5 wherein at least the discharge end of said internal liquid inlet conduit is normal to said standpipe, and wherein an extension of the longitudinal axis of said inlet conduit intersects an extension of the longitudinal axis of said standpipe.

7. The apparatus defined in claim 5 wherein the distance between the end of said internal liquid inlet conduit and the centerline of said standpipe is equivalent to /2 to 2 times the diameter of said standpipe and the distance between the inlet terminus of said standpipe and the centerline of said internal liquid inlet conduit is equivalent to about V2 to 2 times the diameter of said internal liquid inlet conduit.

8. The apparatus defined in claim 5 wherein the inlet terminus of said standpipe is adjacent to the top of said vessel.

9. The apparatus defined in claim 5 wherein the inlet terminus of said standpipe is adjacent to the bottom of said vessel.

10. Apparatus for dispersing buoyant particles of solid material in a liquid, which comprises:

an elongated, closed vessel adapted to contain a bulk quantity of the particulated solid material in a reservoir of the liquid;

means to support said vessel in a substantially vertical positron; a liquid outlet connection in the bottom of said vessel; an internal standpipe vertically supported within said vessel to communicate the interior of said vessel with said outlet connection, said standpipe having an open inlet terminus in an upper section of said vessel through which the contents of the vessel are withdrawn; a liquid inlet connection in said vessel; and an internal liquid inlet conduit within said'vessel to communicate said inlet connection with the interior of said vessel, said inlet conduit terminating adjacent to the open inlet terminus of said standpipe wherein an extension of the longitudinal axis of said inlet conduit intersects an extension of the longitudinal axis of said standpipe, and wherein the distance between the end of said internal liquid inlet conduit and the centerline of said standpipe is equivalent to /2 to 2 times the diameter of said standpipe and the distance between the inlet terminus of said standpipe and the center line of said liquid inlet conduit is equivalent to about A to 2 times the diameter of said liquid inlet conduit. 11. A method for dispersing particles of a solid material into a flowing liquid, which comprises:

establishing in a closed vessel having an outlet standpipe therewithin through which the contents of said vessel are withdrawn a reservoir of liquid containing a bulk quantity of said particulate solid material;

introducing an additional quantity of liquid into said vessel at a location adjacent the upper terminus of said standpipe; and

withdrawing from said vessel through said standpipe a liquid containing dispersed particles of said solid material.

12. The method defined in claim 11 wherein said liquid is injected into said vessel in a direction normal to the axis of said standpipe.

13. The method defined in claim 11 including the step of regulating the velocity of said liquid injected into said vessel to control the concentration of said solid material dispersed in said liquid withdrawn from said vessel.

14. The method defined in claim 11 wherein said solid material is a pariculate well treating material and wherein said liquid containing dispersed particles of said solid material withdrawn from said vessel is injected into a well penetrating a subterranean formation.

15. A method for dispersing particles of a solid well treating material in a liquid injected into a well penetrating a subterranean formation, which comprises: 1

establishing in a closed vessel having an outlet standpip therewithin through which the contents of said vessel are withdrawn a reservoir of liquid containing a bulk quantity of said particulate solid well treating material; introducing an additional quantity of liquid into said vessel at a location adjacent the upper terminus of said standwithdrawing from said vessel through said standpipe a liquid containing dispersed particles of said solid well treating material; and

injecting said liquid containing dispersed particles of solid well treating material into a well penetrating a subterranean formation. 16. The method defined in claim 15 wherein said liquid is injected into said vessel in a direction normal to the axis of said standpipe.

17. The method defined in claim 15 including the step of regulating the velocity of said liquid injected into said vessel to control the concentration of said well treating agent dispersed in said liquid withdrawn from said vessel.

18. A method for dispersing oil-soluble, water-insoluble solid plugging particles in an aqueous liquid injected into a well penetrating a subterranean formation, which comprises:

placing in a closed vessel having an outlet standpipe through which the contents of said vessel are withdrawn an admixture of said oil-soluble, water-insoluble solid plugging particles, a surface active agent and said aqueous liquid;

introducing an additional quantity of liquid into said vessel at a location adjacent to the upper terminus of said standpipe and in a direction normal to the longitudinal axis of said stand pipe;

withdrawing from said vessel through said standpipe a liquid containing dispersed particles of said solid well treating material; and

injecting said aqueous liquid containing dispersed particles of said solid plugging material into a well penetrating a subterranean formation.

19. The method defined in claim 18 including the step of regulating the velocity of said liquid injected into said vessel to control the concentration of solid well treating agent dispersed in said liquid withdrawn from said vessel. 

2. The apparatus defined in claim 1 wherein said internal liquid inlet conduit is adapted to discharge liquid into said vessel across the open inlet terminus of said standpipe in a direction normal to the longitudinal axis of said standpipe.
 3. The apparatus defined in claim 1 wherein the inlet terminus of said standpipe is located in an upper section of said vessel, wherein said liquid inlet connection is located in the side wall of said vessel and wherein said internal liquid inlet conduit projects from said liquid inlet connection horizontally into said vessel so as to discharge liquid into said vessel across the inlet terminus of said standpipe.
 4. The apparatus defined in claim 1 wherein the inlet terminus of said standpipe is located in a lower section of said vessel, wherein said liquid inlet connection is located in the side wall of said vessel, and wherein said internal liquid inlet conduit projects from said liquid inlet connection horizontally into said vessel so that the liquid discharged into said vessel passes across the open inlet terminus of said standpipe.
 5. Apparatus for dispersing particles of solid material in a liquid, which comprises: an elongated, closed vessel adapted to contain a bulk quantity of the particulated solid material in a reservoir of the liquid; means to support said vessel in a substantially vertical position; an outlet connection in the bottom of said vessel; an internal standpipe vertically supported within said vessel to communicate the interior of the vessel with said outlet connection, said standpipe having an open inlet terminus through which the contents of the vessel are withdrawn; a liquid inlet connection in said vessel; and an internal liquid inlet conduit within said vessel to communicate said inlet connection with the interior of said vessel, said conduit being adapted to discharge said liquid into said vessel across the inlet terminus of said standpipe.
 6. The apparatus defined in claim 5 wherein at least the discharge end of said internal liquid inlet conduit is normal to said standpipe, and wherein an extension of the longitudinal axis of said inlet conduit intersects an extension of the longitudinal axis of said standpipe.
 7. The apparatus defined in claim 5 wherein the distance between the end of said internal liquid inlet conduit and the centerline of said standpipe is equivalent to 1/2 to 2 times the diameter of said standpipe and the distance between the inlet terminus of said standpipe and the centerline of said internal liquid inlet conduit is equivalent to about 1/2 to 2 times the diameter of said internal liquid inlet conduit.
 8. The apparatus defined in claim 5 wherein the inlet terminus of said standpipe is adjacent to the top of said vessel.
 9. The apparatus defined in claim 5 wherein the inlet terminus of said standpipe is adjacent to the bottom of said vessel.
 10. Apparatus for dispersing buoyant particles of solid material in a liquid, which comprises: an elongated, closed vessel adapted to contain a bulk quantity of the particulated solid material in a reservoir of the liquid; means to support said vessel in a substantially vertical position; a liquid outlet connection in the bottom of said vessel; an internal standpipe vertically supported within said vessel to communicate the interior of said vessel with said outlet connection, said standpipe having an open inlet terminus in an upper section of said vessel through which the contents of the vessel are withdrawn; a liquid inlet connection in said vessel; and an internal liquid inlet conduit within said vessel to communicate said inlet connection with the interior of said vessel, said inlet conduit terminating adjacent to the open inlet terminus of said standpipe wherein an extension of the longitudinal axis of said inlet conduit intersects an extension of the longitudinal axis of said standpipe, and wherein the distance between the end of said internal liquid inlet conduit and the centerline of said standpipe is equivalent to 1/2 to 2 times the diameter of said standpipe and the distance between the inlet terminus of said standpipe and the center line of said liquid inlet conduit is equivalent to about 1/2 to 2 times the diameter of said liquid inlet conduit.
 11. A method for dispersing particles of a solid material into a flowing liquid, which comprises: establishing in a closed vessel having an outlet standpipe therewithin through which the contents of said vessel are withdrawn a reservoir of liquid containing a bulk quantity of said particulate solid material; introducing an additional quantity of liquid into said vessel at a location adjacent the upper terminus of said standpipe; and withdrawing from said vessel through said standpipe a liquid containing dispersed particles of said solid matErial.
 12. The method defined in claim 11 wherein said liquid is injected into said vessel in a direction normal to the axis of said standpipe.
 13. The method defined in claim 11 including the step of regulating the velocity of said liquid injected into said vessel to control the concentration of said solid material dispersed in said liquid withdrawn from said vessel.
 14. The method defined in claim 11 wherein said solid material is a pariculate well treating material and wherein said liquid containing dispersed particles of said solid material withdrawn from said vessel is injected into a well penetrating a subterranean formation.
 15. A method for dispersing particles of a solid well treating material in a liquid injected into a well penetrating a subterranean formation, which comprises: establishing in a closed vessel having an outlet standpipe therewithin through which the contents of said vessel are withdrawn a reservoir of liquid containing a bulk quantity of said particulate solid well treating material; introducing an additional quantity of liquid into said vessel at a location adjacent the upper terminus of said standpipe; withdrawing from said vessel through said standpipe a liquid containing dispersed particles of said solid well treating material; and injecting said liquid containing dispersed particles of solid well treating material into a well penetrating a subterranean formation.
 16. The method defined in claim 15 wherein said liquid is injected into said vessel in a direction normal to the axis of said standpipe.
 17. The method defined in claim 15 including the step of regulating the velocity of said liquid injected into said vessel to control the concentration of said well treating agent dispersed in said liquid withdrawn from said vessel.
 18. A method for dispersing oil-soluble, water-insoluble solid plugging particles in an aqueous liquid injected into a well penetrating a subterranean formation, which comprises: placing in a closed vessel having an outlet standpipe through which the contents of said vessel are withdrawn an admixture of said oil-soluble, water-insoluble solid plugging particles, a surface active agent and said aqueous liquid; introducing an additional quantity of liquid into said vessel at a location adjacent to the upper terminus of said standpipe and in a direction normal to the longitudinal axis of said stand pipe; withdrawing from said vessel through said standpipe a liquid containing dispersed particles of said solid well treating material; and injecting said aqueous liquid containing dispersed particles of said solid plugging material into a well penetrating a subterranean formation.
 19. The method defined in claim 18 including the step of regulating the velocity of said liquid injected into said vessel to control the concentration of solid well treating agent dispersed in said liquid withdrawn from said vessel. 